[Python-Dev] Re: Be Honest about LC_NUMERIC [REPOST]

[Jeff Epler]

On Tue, Sep 02, 2003 at 11:29:55AM -0400, Tim Peters wrote:
> OTOH, *are* there locales that insert thousands_sep?  I don't know.
[...]
> There's no support there for the notion that "the formatted (etc)" functions
> *can* be affected by thousands_sep, just that fiddling locale can affect
> decimal-point and the (passive) values returned by localeconv().

The Linux/glibc documentation, which cites SUSv2, seems to imply that no
locale inserts the thousands separator in formatting operations, except
when the ' flag character is included:
       For  some  numeric  conversions  a radix character ('decimal point') or
       thousands' grouping  character  is  used.  The  actual  character  used
       depends on the LC_NUMERIC part of the locale. The POSIX locale uses '.'
       as radix character, and does not have a grouping character.  Thus,
                   printf("%'.2f", 1234567.89);
       results in '1234567.89' in the POSIX locale,  in  '1234567,89'  in  the
       nl_NL locale, and in '1.234.567,89' in the da_DK locale.
[...]
       The  five  flag  characters  above  are defined in the C standard.  The
       SUSv2 specifies one further flag character.

       '      For decimal conversion (i, d, u, f, F, g, G) the output is to be
              grouped with thousands' grouping characters if the locale infor-
              mation indicates any.  Note that many  versions  of  gcc  cannot
              parse  this  option  and  will  issue a warning.  SUSv2 does not
              include %'F.

Jeff